The invention generally relates to locks, and more particularly relates to a locking arrangement for preventing a key from being pulled out of an ignition starting switch of a motor vehicle.
DE 43 32 478 C2 discloses a locking arrangement for preventing a key from being pulled out of an ignition starting switch of a motor vehicle with automatic or manual transmission. The locking arrangement operates depending on the transmission being shifted in the xe2x80x9cparkxe2x80x9d or xe2x80x9clockedxe2x80x9d gear position in which the driving wheels of the motor vehicle are blocked. In this case, an electromagnetic or electromechanic locking mechanism that is connected to a switching contact of the transmission cooperates with a locking shoulder that is arranged on the rotor of the ignition starting switch and prevents the ignition starting switch from being turned into a position in which the key can be pulled out depending on the gear position of the transmission. The locking mechanism on the ignition starting switch consists of an electromagnet with a spring-loaded plunger that blocks the moving path of the rotor containing the locking shoulder with a projection arranged on its free end in the xe2x80x9ckey lockedxe2x80x9d position. In this locking arrangement, the housing of the ignition starting switch which accommodates the locking mechanism needs to be designed relatively large in order to accommodate the corresponding components. In addition, the housing is fixed on the steering column jacket of the motor vehicle. The locking mechanism and the ignition starting switch are also electrically separated from one another. This results in a significant installation expenditure because separate supply lines need to be installed and connected for the locking mechanism, as well as for the ignition starting switch.
EP 0 646 939 A1 also discloses an ignition starting switch for a motor vehicle which contains a receptacle for an auxiliary device that cooperates with the ignition starting switch, e.g., a locking arrangement for preventing pulling of the key out of the ignition starting switch. The housing of the ignition starting switch contains a laterally protruding housing projection that is provided with a receptacle opening, into which an insert with the auxiliary device can be inserted. The insert completely covers the receptacle opening and is fixed on the housing projection by means of a separable snap-on connection. Although a mechanical coupling with the auxiliary device is realized in this ignition starting switch, an electric connection with the auxiliary device is not produced so that separate supply lines for the ignition starting switch and the auxiliary device inserted into its housing also need to be provided in this case.
The invention is based on the objective of developing a locking arrangement of the initially described type for preventing pulling of a key out of an ignition starting switch of a motor vehicle, wherein said locking arrangement can be easily installed, has a compact design and can be inexpensively manufactured.
According to the invention, this objective is attained by respectively inserting the locking mechanism and the ignition starting switch into separate openings in the housing of a steering column switch that is rigidly arranged on the steering column jacket, wherein the locking mechanism is mechanically interlocked with the housing of the steering column switch after being inserted therein and electrically connected to contacts of the ignition starting switch via terminal contacts, and wherein the ignition starting switch is connected to an on-board network via a printed circuit board arranged in the housing of the steering column switch.
These measures result in a locking arrangement that has a very compact design because the locking mechanism and the ignition starting switch are directly inserted into separate openings of the steering column switch housing. The simple installation is achieved due to the fact that the locking mechanism is interlocked with the steering column switch housing after being inserted therein, with the electric connection between the ignition starting switch and the locking mechanism simultaneously being produced. This eliminates the need for additional connecting lines that connect the locking mechanism to the on-board network. The printed circuit board that is connected to the ignition starting switch represents the only connection with the on-board network that also comprises the switching contact of the transmission. In addition, no separate housing needs to be provided for the ignition starting switch held in the steering column switch housing.
The locking mechanism preferably comprises a modular housing that is composed of a lower housing part and an upper housing part and serves for accommodating a coil element with terminal contacts that are realized in the form of tuning fork contacts and arranged on its end face. The tuning fork contacts ensure that a reliable connection with the contacts of the ignition starting switch can be easily produced. Since the components are accommodated in the modular housing of the locking mechanism, they are protected from becoming damaged while there are handled, i.e., while being transported, stored and installed. Due to this design, the locking mechanism can, if so required, also be inserted into the steering column switch housing in the form of a separate module. In this case, the proper function of the ignition starting switch is also ensured if no locking mechanism is inserted.
In order to separably mount the locking mechanism in the steering column switch housing, the lower housing part preferably contains a clip-on arm for being mechanically interlocked with the steering column switch housing. The lower housing part and the clip-on arm are integrally manufactured by means of an injection molding process.
In order to achieve an installation that requires hardly any tools and can be automated relatively easily, the lower housing part and the upper housing part of the modular housing are held together by means of snap-on elements, and the tuning fork contacts protrude from a corresponding opening in the lower housing part.
According to one advantageous additional embodiment of the invention, a spring-loaded locking disk with a catch is rotatably supported in the upper housing part above the tuning fork contacts, wherein the catch protrudes from an opening in the modular housing and cooperates with the detent pawl of the ignition starting switch on one hand and with the locking pin on the other hand in the locked position in which the key cannot be pulled out of the ignition starting switch. The catch that is acted upon by the locking pin cooperates with the detent pawl mounted on the rotor of the ignition starting switch in such a way that the ignition starting switch cannot be turned into a position in which the key can be pulled out. The catch held in the locked position by the locking pin merely prevents the ignition starting switch from being turned into a position in which key can be pulled out. This means that the ignition starting switch can still be turned in the opposite direction, for example, for starting the engine of the motor vehicle.
The modular housing preferably contains a taper in the region of the ignition starting switch, wherein the opening for the catch is arranged in the region of this taper. The taper causes the axis of rotation of the catch to be situated relatively close to the axis of rotation of the detent pawl such that favorable lever ratios and low mechanical stress are ensured. A compact structural shape is simultaneously achieved.
In order to achieve a relatively high stability and functional reliability with a low material expenditure, the catch preferably is realized essentially right-angled, wherein one limb protrudes over the taper of the modular housing in the locked position and acts upon a locking surface of the detent pawl while the locking pin engages behind the other limb.
In order to effectively secure the catch from being turned without requiring additional components, the limb of the catch which acts upon the locking surface of the detent pawl adjoins an assigned housing wall in the locked position.
According to one advantageous embodiment of the invention, the catch can be positively controlled by the detent pawl against the effect of a torsion spring in a neutral position in which the key can be pulled out of the ignition starting switch, namely while the corresponding limb of the catch adjoins the detent pawl. An outer corner point of the catch limb assigned to the detent pawl always adjoins the periphery of the detent pawl due to the spring effect. When the locking position is reached, the torsion spring turns the catch in the corresponding direction, and the limb that adjoins the detent pawl comes in contact with the locking surface.
In order to achieve a stable design, the coil element preferably is realized in an essentially U-shaped fashion, wherein a coil is arranged between the limbs. The coil carries one limb of the tuning fork contacts, and the locking pin extends through both limbs, as well as the coil. The tuning fork contacts are surrounded by the material of the coil element or are extrusion-coated just like the coil during the manufacture of the coil element.
The locking pin preferably comprises a head and an actuating projection for the catch, with a compression spring being arranged between the head and one limb of the coil element, namely on a guide projection of the locking pin. The metallic locking pin consequently represents a spring-loaded rotary part of relatively simple design.
In the neutral position, the head of the locking pin advantageously adjoins a limit stop of the upper housing part under the influence of the compression spring, with the actuating projection releasing the assigned limb of the catch of the locking disk. This means that the neutral position, in which the key can be pulled out of the ignition starting switch and the ignition starting switch can be turned into arbitrary switching positions, is maintained in a purely mechanical fashion by the compression spring. In addition, the locking pin is held between the limit stop and the assigned limb of the coil element in a captive fashion.
The coil preferably attracts the locking pin in the locked position in the axial direction against the effect of the compression spring. In order to attract and thusly axially displace the locking pin in the direction of the catch of the locking disk, it is necessary to supply the coil with power via the ignition starting switch depending on the gear position of the transmission. The coil receives a signal regarding the gear position of the transmission via one of the tuning fork contacts connected to the contacts of the ignition starting switch, wherein the ignition starting switch is connected to the switching contact of the transmission via the printed circuit board.
According to another advantageous embodiment of the invention, the ignition starting switch comprises at least one displaceable contact that is realized in the form of a contact spring and acts upon a contact path for supplying the coil with power when the key is inserted. This alleviates the battery of the motor vehicle during the time at which no key is inserted into the ignition starting switch. In addition, the coil is not heated so its service life is extended.
In order to also disengage the battery during the operation of the motor vehicle, the power supply of the coil preferably is dependent on the rotational position of the key. The coil does not require current while the engine of the motor vehicle is running, but only when the key and consequently the ignition starting switch are turned in order to switch off the engine or into a position in which the key can be pulled out of the ignition starting switch.
The steering column switch housing preferably accommodates other individual switches that are coupled to the printed circuit board. This means that the printed circuit board arranged within the steering column switch housing fulfills a series of functions.
In order to simplify the installation, the steering column switch housing contains guide means for unmistakably inserting the modular housing of the locking mechanism. The guide means protect the tuning fork contacts of the locking mechanism and the contacts of the ignition starting switch from damage when the locking mechanism is inserted into the steering column switch housing.
In order to fix the position of the components relative to one another, a web is preferably arranged between the contacts of the ignition starting switch, wherein said web engages into a corresponding recess between the tuning fork contacts of the locking mechanism. Due to this measure, the tuning fork contacts of the locking mechanism are fixed in their position relative to the contacts of the ignition starting switch.
In order to ensure that the available space of the steering column switch housing is optimally utilized in the region of the ignition starting switch and to provide an additional safety device, preferably a transponder coil for a drive-away lock which is functionally connected to a transmitter of the key is assigned to the ignition starting switch, wherein said transponder coil is inserted into the steering column switch housing and connected to the printed circuit board.
The previously described characteristics, as well as the characteristics described below, cannot only be used in the respectively described combination, but also in other combinations without deviating from the scope of the present invention.